3-pyrazolidones



2,772,282 Patented Nov. 27, 1956 United States Patent It y 2 CH: 2,772,282 S-PYRAZOLIDONES 5 H-N orn Charles F. H. Allen and John R. Byers, Jr., Rochester, N. Y., assignors to Eastman Kodak Company, Roch- N ester, N. Y., a corporation of New Jersey No Drawing. ApplicafionAugust 3,1953,

Serial No. 372,148

8 Claims. (Cl. 260-310) i 1-p-amin op11eny1-4methyl-*kpropyl-3-pyrazolidone This invention relates to the preparation of 3-pyrazo1i- 15 done compounds and particularly to the preparation of 4,4-dialkyl-3-pyrazolidones. 0=CO Various 3-pyrazolidones have been described in the I l prior art such as 1-phenyl-3-pyrazolidone and I-phenyh 5-1nethyl-3-pyrazolidone having the respective structures However, the 4,4-dialky1-S-pyrazolidones have not pre- C H 1 viously been described and have unusual PIOPEIUBS par- 2 G ticularly as photographic developing agents.

The 4,4-dialkyl-3-pyrazo1idones of the invention have 01H: the general formula OH:

R: \N/ 0=0 ER,

HN H2 NHCOCH:

wherein R represents an alkyl group preferably of 1 to 4 1-p acetamidopheny1-4,4diethy1-3-pyrazo1idone carbon atoms such as methyl, ethyl, n-propyl, lso-butyl;

or an aryl group of the benzene or naphthalene series OH: substituted or not such as phenyl, o-tolyl, m-tolyl, p-tolyl, 0:0 p-aniinophenyl, o, 111-, p-methoxyphenyl, p-dialkylarninophenyl, o-nitrophenyl, o-brornopheny1, o-chlorophenyl, I m-nitrophenyl, m-bromophenyl, m-chlorophenyl, p-nitro- H-N 01-1 phenyl, p-benzylphenyl, p-brornophenyl, p-chlorophenyl, p-acetamidophenyl, 0-, m-, p-carboxyphenyl, p-cyanophenyl, hydroxyalkylphenyl such as p-hydroxyethylphenyl, o-, m-, p-hydroxyphenyl, as well as u-naphthyl, /3-naphthyl, 7-hydroxy-2-naphthyl, and other aryl groups derived from aryl hydrazines. R1 and R2 represent the same or different alkyl groups preferably containing from OHEGEOH 1 to 4- carbon atoms such as those above mentioned.

The following are representative compounds forming 1p-,B-hydroxyethylpheny1-4A-dimethy1-3-pyraz0lidone a part of our invention.

C a o=o-o 0=oo H--N on, HN on:

1-pheny1-&,i-dhnethy1-3-pyrazo1idone l-p-hydroxyphenyl-4,4-dimethyl-Zl-pyrazolidone OCH;

1-p-methoxyphenyl-4,4-diethy13-pyrazolidone 1-p-toly1-4A-dimethyl-3pyrazo1idone 1- 7 -hyd1.'oxy-2-I1aphthyl -4-n1ethy1-4.-n-pr0pyl-3-pyrazolidone Examples of other 3-pynazolidones contemplated are:

1-p-nitrophenyl-4,4-dimethyl-3-pyrazolidone 1-p-cyanophenyl-4,4-dimethyl-3 -pyrazolidone l-p-acetylaminophenyl-4,4-dimethyl-3 -pyrazolidone 1-p-benzylphenyl-4,4-dimethyl-3 pyrazo1idone 1-methyl-4,4-dimethyl-3-pyrazolidone 1-p-carboxyphenyl-4,4-dimethyl-3-pyrazolidone 1-carboxymethyl-4,4-dimethyl-3 -pyrazolidone 1-hydroxyethyl-4,4-dimethyl-3 -pyrazolidone 1-m-aminophenyl-4,4-dimethyl-3pyrazolidone 1-m-chlorophenyl-4-methyl-4-ethyl-3 -pyrazolidone 1-m-acetamidophenyl-4,4-diethyl-3 -pyrazolidone The 4,4-dialkyl-3-pyrazolidone compounds of the invention are prepared by a novel method. A hydrazine, such as an arylhydrazine of the benzene or naphthalene series such as phenylhydrazine, is generally reacted with approximately a molecular equivalent amount of a 3- halogen-2,2-dialkyl propionyl halide such as 3-chloro-2,2- dimethylpropionyl chloride in the presence of an acid binding agent such as sodium carbonate, sodium acetate, methyl morpholine, pyridine, quinoline, isoquinoline, dialkylanilines, such as diethylaniline, trialkylarnines such as triethylamine and N-alkylpiperidines. In effecting the reaction it appears essential that the mentioned ingredients be combined within a rather limited range of temperature of the order of to 10 C. in order to prevent side reactions such as the formation of a S-pyrazolidone compound which materially reduces the yield of the desired product. In addition, we find that after combining the ingredients as mentioned, the yield of product is greatly increased by gradually warming up the reaction mixture as over a steam bath, and maintaining the temperature of the reaction mixture at about 100 C. until the reac tion is complete. For this purpose heating of the reaction mixture over a steam bath for about 1 to 10 hours produces the best yields. 'For example, one hour heating yields 40 percent and 4 hours heating yields percent of the theoretical amount of the 3-pyrazolidone compound. Longer heating can be expected to increase the yield somewhat and it is apparent that it is preferred that the heating be carried out for at least 4 to 5 hours or for an equivalent length of time if heating is conducted at a temperature differing appreciably from steam bath temperature.

3-*halogen-2,2-dialkyl propionyl halides used in preparing the 4,4-dialkyl-3-pyrazolidones of the invention have the structure in which X is a halogen atom and R1 and R2 are alkyl groups and can be prepared as described by Kharasch and Brown, I. A. C. S. 62, 925929 (1940). 3-chloro- 2,2-dimethylpropionyl chloride prepared by that process from sulfuryl chloride and trimethyl acetic acid had a boiling point of -86 C. at 60 mm. and the refractive index was (n l.4539). A satisfactory procedure is as follows:

3-CHLORO-2,Z-DIMETHYLPROPIONYL CHLORIDE OHaOH (OHOBOCOONSI S0012 CHgCl (CHaMCOOCl SO; HC1+ NaO To 156 g. (1.15 moles) of sodium hydroxypivalate in a 500-ml. three-necked flask fitted with a reflux condenser and dropping funnel, 250 ml. (3.44 moles) of thionyl chloride is added slowly. The initial exothermic reaction is followed by an endothermic one. After the addition is complete, the mixture is heated on the steam cone for two hours, and occasionally shaken. The mixture is then distilled at water-pump pressure. The thionyl chloride is not condensed; the chloride is collected at 97-1 12/ mm. The yield is 110-120 g. (62-68%).

3-chloro-Z,2'dipropylpropionylhalide can be made in a similar manner. In the case of these propionyl halides the alkyl groups in the 2-position of the propionyl halides are identical, and when these propionyl halides are reacted with the hydrazines, the resulting 3-pyrazolidone compounds contain identical alkyl groups in the 4-position (R and R2 in the above formulas).

The 4,4-dialkyl-3-pyrazolidones having the above formula in which R and R2 are different alkyl groups are preferably prepared by reaction of the selected arylhydrazine with propionyl halides having the above formula in which R and R2 are different alkyl groups. These propionyl halides can be prepared from disubstituted acetaldehydes (R1RzCHCHO) such as methylpropyl acetaldehyde by reaction with formaldehyde and alkali to obtain the corresponding hydroxymethyl disubstituted acetaldehydes (RiRzCCHO) OHZOH such as hydroxymethyl-propylmethylacetaldehyde, followed by oxidation to obtain a hydroxymethyl disuhstituted acetic acid, i. e.

HOCE'T EHRQCOOH HOCHflIHOHQOOOH 03131 which is then treated with thionyl chloride to obtain the desired 2,2-dialkylsubstituted-3-chloropropionyl chloride such as 2,2-methylpropyl-3-chloropropionyl chloride which is then reacted with the selected hydrazine to obtain the corresponding 4,4-disubstituted-3-pyrazolidone.

The 1 hydroxyalkylaryl 4,4 dialkyl 3-pyrazolidone compounds having the above general formula wherein R represents a hydroxyalkylphenyl group, are prepared by the reaction of acetoxyalkylphenylhydrazines with the above described 2,2 disubstituted 3 chloropropionyl halides, followed by acidic or basic hydrolysis of the resulting 1-acetoxyalkylphenyl-4,4-dia1kyl-3-pyrazolidone as described in the following examples.

1-hydroxyphenyl-4,4-dialkyl-3-pyrazolidones are prepared from acyloxyphenylhydrazines such as p-acetoxyphenylhydrazine reacted with the selected 2,2-dialkyl substituted 3-chloropropionyl chloride, such as 2,2-dimethyl- S-chloropropionyl chloride in the manner of the following examples, and subsequently hydrolyzing the resultant 1-acyloxyphenyl-4,4-dialkyl-S-pyrazolidone. The comparable 1-naphtho1-4,4-dialkyl-3-pyrazolidones are prepared similarly from the acetoxynaphthylhydrazines.

The 1-arnin0phenyl-4,4-disubstituted S-pyrazolidones can be prepared similarly by reacting the selected acylaminophenyl'hydrazine such as p-acetaminophenylhydrazine with the selected 2,2-disubstituted-3-chloropropionyl chloride, e. g, 2,2-dimethyl-3-chloropropionyl chloride, followed by saponification of the resultant amide.

The 1-aminoaryl-4,4-diallcyl-3-pyrazolidone compounds can also be obtained by our process by utilizing a nitrophenyl hydrazine, such as p-nitrophenylhydrazine for reaction with the acid chloride followed by reduction of the nitro group of the resulting 1-nitroaryl-4,4-dialkyl-3- pyrazolidone.

The 1-alky1*4,4-dialkyl-3-pyrazolidones are prepared by reaction of aikylhydrazines such as methylhydrazine or carboxymethylhydrazine, with the 3-halogen-2,2-dialkylpropionyl halides such as 3-chloro-2,2-dimethylpropionyl chloride. Thus, in this case 1-methyl-4,4-dimethyl-3-pyrazolidone is obtained from methylhydrazine.

Detailed preparation of representative compounds of our invention will now be described.

such as in a 1-liter 3-necked fiask equipped with a mechanical stirrer, a thermometer, and a dropping funnel are placed 240 ml. of dry pyridine and 60 ml. (66 g., 0.56 mole) of phenylhydrazine. The mixture is cooled to 5, and the addition of 60 ml. (71 g., 0.46 mole) of 3-chloro- 2,2-dirnethylpropionyl chloride begun. The mixture is kept below 25 during the addition, allowed to warm to room temperature during one hour or overnight and finally refluxed for two hours.

The mixture is cooled, diluted with 300 ml. of chloroform, and extracted with several portions of 5l0% aqueous sodium hydroxide. Each extract is washed twice with a little chloroform, neutralized (to pH 6, universal indicator paper) with concentrated hydrochloric acid, cooled, and filtered. The first extracts are neutralized by the pyridine hydrochloride and yield no pyrazolidone. From later portions are obtained 64 g. (74%) of crude material. Recrystallization from aqueous methanol yields 59 g. (68%); M. P. 164166 (uncon). The hydrazine salts, e. g., phenylhydrazine hydrochloride can also be used in the above synthesis.

EN 0 H:

2-chloro-1,l-dimethylpropionyl chloride (14 g.; 0.1 mole) is dissolved in 25 ml. of pyridine which has been cooled to 5 in :an ice bath. This solution is added in four portions at 5 during 5 minutes to a slurry of 16 g. of p-tolyl-l-iydrazine hydrochloride in 15 ml. of pyridine. The mixture is heated on the steam bath until all has dissolved, and then heated for four more hours. Cold water (350 ml.) is stirred in during 15 minutes. The solution is scratched to start crystallization, cooled to 5, and filtered. There is thus obtained 12.4 g. of crude 1-p-tolyl--4,4-dimethyl-3-pyrazolidone (M. P. 143145) which is 60% of the theoretical amount of 20.4 g.

Purification is eiiected by dissolving in 55 ml. of absolute alcohol and treating with Norit. The hot filtered solution is cooled to 5 and again filtered. The crystallino product is washed well with petroleum ether to remove a yellow impurity and dried. The melting range is then 148149.

The isomeric ortho and meta-tolyl compounds l-otolyl-4,4-dimethyl-3-pyrazo1idone M. P. 143-144 C., and 1-m-tolyl-4,4-dimethyl-3-pyrazolidlone M. P. 107 C., are prepared by the above method using the corresponding .orthoand meta-tolylhydrazines or their salts.

Example 3. 1- (p-fi-hydroxyethylphenyl) -4,4-dimethyl- 3-pyraz0lid0ne p(B-Acetoxyethyl)phenylhydrazine hydrochloride was prepared by diazotization of 33 g. of p-(B-acetoxyethyD- aniline followed by reduction of the resulting diazonium compound with 85.5 g. stannous chloride dihydrate. The diazonium compound was extracted with ether, Washed with water, and dried over magnesium. sulfate The hydrazine HCl derivative was precipitated by bubbling I-ICl through the ether solution until no additional product separated.

The desired 3-pyrazolidone derivative was obtained by mixing an externally cooled solution of 1.6 g. of (pacetoxyethyl) phenylhydrazine hydrochloride in 8 ml. of dry pyridine and 1.08 g. of 3-chloro-2,2-dimethylpropionyl chloride, followed by refluxing the reaction mixture for 2 hours. The resulting l-(p-fi-acetoxyethylphenyl)-4,4-dimethyl-3-pyrazolidone, after further extraction and recrystallization, had a. melting point of 81.5-83.5 C.

A solution of 0.2 gram of 1,4--(p-fi-acetoxyethylphenyl)-4-,4-dimethyl-3-pyrazolidone in 10 m1. of 2% hydrogen chloride-methanol Was refluxed 3 /2 hours and evaporated to dryness under reduced pressure. The residue was taken ofi in 4 ml. of 5% sodium hydroxide and the small quantity of base-insoluble material was removed by an ether extraction. The basic solution was acidified to pH 6 with concentrated H'Cl, saturated with sodium chloride and extracted three times with ether. The ether extract was washed once with saturated brine and dried. Evaporation of the ether yielded a glossy solid which was crystallized from a mixture of ethyl acetate and ligroin, yield 0.1 gram, melting point C. Recrystallization of this product from the same solvent pair and treatment with Norit raised the melting point to 140-1435" C.

Representative arylhydrazines and alkylhydrazines useful in preparing the compounds of the invention are, for example:

Phenylhydrazine 111-, p-"folylhydrazine 0-, m-, p-Bromophenylhydrazine o-, m-, p-Methoxyphenylhydrazines o-, m-, p-Nitrophenylhydrazines o-, m-, p-Chlorophenylhydrazines p-Cyanophenylhydrazine o-, m-, p-Bromophenylhydrazines p-Acetamidophenylhydrazine p-Benzylphenylhydrazine p-Diethylaminophenylhydrazine Methylhydrazine Ethylhydrazine o-, m-, p-Carboxyphenylhydrazine* o-, m-, p-Acetoxyphenylhydrazines p-Acetoxyethylphenylhydrazine Carboxymethylhydrazine Carboxyethylhydrazine Acetoxyethylhydrazine wNaphthylhydrazine 7-acetoxy-2-naphthylhydrazine As will be apparent, representative 3-halogen-2,2- dialkylpropionyl halides which can be reacted with the above hydrazines to obtain the 4,4-dialkyl-3-pyrazolidone compounds of the invention are:

3-chloro-2,2-dimethylpropiony1 chloride 3-bromo-2,2-dimethylpropionyl bromide 3-chloro-2,2-diethylpropionyl chloride 3-chloro-2,2-dipropylpropionyl chloride 3-chloro-2,2-dibutylpropionyl chloride 3-chloro-Z-methyl-2-ethylpropionyl chloride 3-chloro-2-methy1-2-propylpropionyl chloride As previously mentioned, the 4,4-dia1kyl-3-pyrazolidone compounds of the invention have unique properties as photographic developing agents. It is not understood why this is true; however, it has been observed that when the compounds are used as developing agents in photographic developer compositions for the development of exposed silver halide emulsion layers, the oxidation products of the 4,4-dialkyl-3-pyrazolidone compounds obtained as a result of the development reaction are bimolecular compounds believed to have the following structure:

Where the R groups in the formula are those given above. In the case of l-phenyl-4,4-dimethyl-3-pyrazolidone, the bimolecular development product had a melting point of 181-183 C. and had the following analysis:

Calcd.: c, 70.2; H, 6.4; N, 14.9; M. wt., 376

Found: C, 70.2; H, 7.0; N, 14.8; M. wt., 366 (boiling ethyl alcohol) The mentioned prior art compounds such as 1-phenyl-3- pyrazolidone, which contain hydrogen atoms in both the 4 and 5 positions of the pyrazolidone nucleus, are believed to form during the development of silver halide emulsions the corresponding 3-hydroxy-l-phenylpyrazole, rather than a bimolecular compound obtained from the 4,4-dialkyl-3-pyrazolidone compounds of the invention.

It is not understood what mechanism is involved which renders the 4,4-dialkyl-3-pyrazolidone compounds of the invention superior to the mentioned prior art l-aryl-3- pyrazolidone compounds as developing agents in photography. However, the superiority of the compounds of the invention was particularly evident when they were used as auxiliary developing agents in developer compositions having relatively low pH. For this purpose the compounds were compared in a well known developer composition compounded as follows:

Gram per liter Experimental developing agent 0.5 Sodium sulfite 100.0 Hydroquinone 5.0 Borax 2.0

Develop- 0.3 Developing Agent ment Gradient Gamma Net Time Speed Fog (min) 3% l, 500 0. 50 0. 27 1-Phenyl-3-pyrazolidonc. 5% l, 250 69 .41 8 900 79 58 11 700 88 72 2% 2, .40 .05 1 Phenyl 4,4 dimethyl 3 5% 2, 650 59 .08 pyrazolidone 8 3, 100 63 11 11 3, 000 74 13 3% 3, 100 40 06 5% 2, 900 53 11 1 p Tolyl 4,4 dimethyl a s 3, s50 .67 .14 pyrazolidone 11 4, 000 76 19 It will be apparent from the above data that the compounds of the invention produce considerably higher speed and considerably less fog in the development of silver halide emulsions than does the 1-phenyl-3-pyrazolidone compound of the prior art. Also, it will be noted from the above data when considering the compounds of the present invention per se, that the substitution of the l-aryl nucleus of the l-aryl-4,4-dialkyl-3pyrazolidone compounds, as in 1-tolyl-4,4-dimethyl3-pyrazolidone, unexplainably increases the effectiveness of the compound as an auxiliary developing agent.

The developing agents were also compared for their stability in developers of relatively high pH of the order of 10. This is, developer compositions of this alkalinity are well known to undergo darkening due to aerial oxidation on standing in open vessels, which shortens their life. For this purpose, three developer compositions of pH 10, each containing one of the three above developing agents in addition to hydroquinone, were aerated for 4 days in open vessels. As a result, the two developer compositions containing the developing agents of the invention darkened measurably less than the developer composition containing l-phenyl-3-pyrazolidone.

What we claim is:

l. A I i-pyrazolidone compound having the general formula /R2 O=C-C wherein R represents a member of the class consisting of phenyl, tolyl, p-fl-hydroxyethylphenyl, and p-fi-acetoxyethylphenyl groups, and R1 and R2 each represent an alkyl group containing from 1 to 4 carbon atoms.

2. 1 phenyl 4,4 dimethyl 3 pyrazolidone.

3. 1 p tolyl 4,4 dimethyl 3 pyrazolidone.

4. 1 o tolyl 4,4 dimethy-l 3 pyrazolidone.

5. 1 m tolyl 4,4 dimethyl 3 pyrazolidone.

6. 1 (p 13 hydroxylethylphenyl) 4,4 dirnethyl- 3 pyrazolidone.

7. A process for preparing a 1-aryl-4,4-dialkyl-3- pyrazolidone which comprises reacting phenylhydrazine with a compound having the general formula wherein R1 and R2 represent alkyl groups each containing from 1 to 4 carbon atoms and X represents a halogen atom, at a temperature of 0 to 10 C. in the presence of an acid binding agent, heating the reaction mixture at a temperature of about 100 C. for about 1 to 10 hours. 8. A process for preparing 1-phenyl-4,4-dirnethyl-3 References Cited in the file of this patent UNITED STATES PATENTS 2,289,367 Kendall July 14, 1942 2,688,024 Kendall et al. Aug. 31, 1954 2,704,762 Kendall 'et al. Mar. 22, 1955 OTHER REFERENCES Lieser et al., Chem. Abst., vol. 45, 001. 5119 1951) 

1. A 3-PYRAZOLIDONE COMPOUND HAVING THE GENERAL FORMULA 